1) Field of the Invention
The present invention relates to a technology for creating a printer profile.
2) Description of the Related Art
A conventional image processing apparatus obtains a desired printer output by converting an input color space into an output color space based on a method of processing as follows:
(1) converting color data included in image data input through a scanner or a monitor into the input color space based on a corresponding profile;
(2) equally dividing the input color space using a color lookup table (hereinafter “LUT”) recorded in the profile corresponding to a printer;
(3) setting an output value at each peak of divided lattice points; and
(4) converting the input color space into an output color space by obtaining the output color data using a predetermined method (e.g., interpolation) based on the output value stored at each peak that has a closest positional relation with the input color data in the divided lattice.
To obtain the output color space using the above method, it is required to create an appropriate printer profile. To create a printer profile, it is necessary to perform calorimetric processing by outputting a color chart including an extremely larger number of color patches than that of a target printer. As a result, the operation of creating the printer profile produces quite a load on processing resources.
To cope with the problem, Japanese Patent Application Laid Open No. 2001-045313 discloses a technology of storing a compensation profile corresponding to a combination of a printing profile and a printer profile separately from the printing profile and the printer profile so that an increase in memory capacity is suppressed when data is stored, and performing a color conversion to obtain a color-matching proof image with a high precision.
Japanese Patent Application Laid Open No. 2001-144976 discloses a technology of selecting an appropriate table from a plurality of existing profiles (tables) based on evaluation using dot gain or the like, and creating a new profile based on the table and colorimetric data for a color chart having a less number of patches.
Furthermore, Japanese Patent Application Laid Open No. 2000-004369 discloses a technology of performing a test image display and a printer output, comparing the color of the displayed image with the color of the printed image, compensating a particular color that does not match each other by referring to a history, and storing corrected output values at the lattice points in an output device profile.
Besides the above disclosures, Japanese Patent Application Laid Open No. 2001-144976 makes it possible to create a profile with a less number of color patches by taking the amount of dot gain as an evaluation standard. However, since a position of an arbitrary color on a recording medium is unchanged, that is, a position of creating a patch is fixed according to an application, a position to be measured is also the same, and even if a state of another position with no patch is changed, it is not possible to respond to the change. In addition, since a patch output at an output position is fluctuated for each representative color (e.g., R, G, B, C, M, Y), colors largely depend on a state of a printer. It is a common problem in the conventional technologies including the above example of disclosures.